1. Field of the Invention
The present invention relates to a method for controlling an optical imaging apparatus including an adaptive optics system. The present invention also relates to a program, a storage medium, and an optical imaging apparatus for implementing the method.
In particular, the present invention relates to a method for controlling an ocular-fundus imaging apparatus having a function of measuring and correcting an aberration of a subject's eye and being capable of obtaining images of the subject's eye at a plurality of resolutions. The present invention also relates to the optical imaging apparatus.
2. Description of the Related Art
Recently, scanning laser ophthalmoscopes (SLO) which two-dimensionally irradiate a fundus with a laser beam and receive light reflected by the fundus and imaging apparatuses using interference of low-coherence light have been developed as ophthalmologic imaging apparatuses.
The imaging apparatuses using the interference of low-coherence light is called optical coherence tomography (OCT) apparatuses, and is used, in particular, to obtain a tomographic image of a fundus or an area around the fundus.
Various types of OCT, such as time domain OCT (TD-OCT) and spectral domain OCT (SD-OCT), have been developed.
In the ophthalmologic imaging apparatuses, recently, the numerical aperture (NA) of the laser has been increased, and the resolution has been increased accordingly.
However, in the process of obtaining an image of a fundus, the fundus is irradiated with a laser beam through optical tissues, such as a cornea and a lens, of an eye.
As the resolution increases, the influence of an aberration of the cornea and the lens on the quality of the obtained image increases.
Accordingly, researches on adaptive optics SLO (AO-SLO) and adaptive optics OCT (AO-OCT) have been conducted. In AO-SLO and AO-OCT, an adaptive optics (AO) system, which is an adaptive optics system for measuring and correcting an aberration of the eye, is adopted. An example of AO-OCT is described in Optics Express, Vol. 14, No. 10, 15 May 2006, by Y. Zhang et al. In AO-SLO and AO-OCT, a wavefront of an eye is generally measured by a Shack-Hartmann wavefront sensor method.
In the Shack-Hartmann wavefront sensor method, the wavefront is measured by causing measurement light to be incident on the eye and receiving light reflected by the eye with a CCD camera through a microlens array. In AO-SLO and AO-OCT, a high-resolution image can be obtained by driving components such as a deformable mirror and a spatial phase modulator so as to correct the measured wavefront and obtaining an image of a fundus through the components. In general, when the NA of the laser is increased to increase the resolution, the amount of aberration caused by the optical tissues, such as the cornea and the lens, of the eye increases accordingly.
The aberration is corrected by the above-described AO. However, there is a limit to the amount by which the wavefront can be corrected by the deformable mirror or the spatial phase modulator. Therefore, there is a risk that the aberration cannot be appropriately corrected depending on the subject's eye.